CA1333654C - Evaporable foam pattern for casting an engine block of a two-cycle engine - Google Patents
Evaporable foam pattern for casting an engine block of a two-cycle engineInfo
- Publication number
- CA1333654C CA1333654C CA 606967 CA606967A CA1333654C CA 1333654 C CA1333654 C CA 1333654C CA 606967 CA606967 CA 606967 CA 606967 A CA606967 A CA 606967A CA 1333654 C CA1333654 C CA 1333654C
- Authority
- CA
- Canada
- Prior art keywords
- pattern
- cylinder
- section
- head
- passage
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B75/00—Other engines
- F02B75/02—Engines characterised by their cycles, e.g. six-stroke
- F02B2075/022—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle
- F02B2075/025—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle two
Landscapes
- Cylinder Crankcases Of Internal Combustion Engines (AREA)
- Exhaust Silencers (AREA)
Abstract
An evaporable foam pattern to be used in casting a multi-cylinder in-line two-cycle engine block. The assembled pattern, which is substantially identical in shape to the cast metal block, includes a plurality of in-line cylinders each having an end open to the crankcase end of the pattern. Each cylinder includes an exhaust passage that communicates with an exhaust manifold that extends to the exterior of the pattern and each cylinder has at least one longitudin-ally extending transfer passage. The assembled pattern also includes cooling passages that surround each cylinder, as well as surrounding the exhaust manifold passage. The foam pattern is composed of a plurality of separate foam sections joined together by an adhes-ive along planar interfaces. A first of the sections extends from the crankcase end of the pattern to the lower end of the transfer passages, and a second section extends from the lower end of the transfer passages to a location intersecting the exhaust passages of the cylinders. A third section extends from the exhaust passages to the cylinder heads. In addition, a fourth pattern section encloses the water passages at the head end of the block, while a fifth section encloses the water passage that borders the exhaust manifold.
Description
I 3336S~
This invention rël;ates generally to evaporable foam patterns for use in casting an engine block of a two-cycle engine.
Cast metal engine blocks for multi-cylinder, in-line, two-cycle engine generally consist of a cylinder block and three separate cast covers, including two water passage covers and an exhaust passage cover, all of which are attached to the cylinder block by bolts. To provide the connection between the covers and the cylinder block, the cylinder block is formed with a series of enlarged lands or bosses, which are drilled or cast and tapped to receive bolts, and similarly mating holes are drilled or cast in the covers. In addition, the mating surfaces between the covers and the cylinder block are machined and the covers are attached to the cylinder block through gaskets and bolts. The gasketed surfaces must be provided with a substantial width to receive the gaskets and prevent leakage between the components.
In the fabrication of a conventional three-cylinder, two-cycle engine, as many as 100 fasteners, such as bolts, screws, and the like, are required to attach the covers to the cylinder block and substantial time and labor is required in machining the interfaces, tapping and drilling holes, applying gaskets and bolting the covers to the block. The intensive labor that is required is a substantial factor in the overall cost of the engine.
Furthermore, the requirement for providing bosses on the cylinder block and the increased width of the gasket surfaces adds to the overall weight of the engine.
In evaporable foam casting processes, a pattern is formed of an evaporable foam material, such as polystyrene. The foam pattern is substantially identical in configuration to the cast metal part to be produced, subject to shrinkage and/or other conditions of the casting process. The foam pattern is placed in a mold and surrounded with a finely divided medium, such as sand, 133365~
which also fills the cavatles in the pattern. When molten metal is introduced into the mold, the molten metal will heat and vaporize the pattern, with the vapor passing into the interstices of the sand, while the molten metal will fill the voids created by vaporization of the foam to provide a cast metal part having substantially the same configuration as the foam pattern. Evaporable foam casting processes have particular advantage when casting parts of unusual or complex contours.
The present invention provides an evaporable foam pattern to be used in casting a two-cycle metal engine block, the assembled pattern comprising a crankcase end and a head end, said pattern including at least one cylinder having an end open to the crankcase end of said pattern and the opposite end enclosed by a head, exhaust passage means connecting said cylinder to the exterior of the pattern, said cylinder having at least one longitudinally extending transfer passage, water cooling passage means bordering said cylinder and said exhaust passage means, said pattern composed of a plurality of separate evaporable foam sections including a first foam section extending from said crankcase end to the corresponding end of said transfer passage, a second pattern section extending from said end of said transfer passage to a location intersecting said exhaust passage, said pattern also including a third section extending from said exhaust passage to said head end including said head, a fourth pattern section disposed at the head end of the pattern and enclosing the portion of said water cooling passage means bordering said cyliner, and a fifth pattern section connected to corresponding sides of said second and third sections and enclosing the side of said water cooling passage means bordering said exhaust passage means.
The assembled foam pattern also includes a network of water cooling passages which surround the cylinders, as well as the exhaust manifold. Water is introduced into the cooling passages through an inlet passage formed in a side surface of the pattern and is discharged from the cooling passages through a discharge passage located adjacent the inlet passage.
Preferably, the evaporable foam pattern is formed of a plurality of foam sections which are joined together by glue or adhesive to provide the assembled pattern.
More particularly, the preferred pattern includes a first pattern section which extends from the crankcase end of the pattern to the lower ends of the transfer passages, and a second section extends from the lower ends of the transfer passages to a location intersecting the exhaust passages of the cylinders.
A third pattern section extends from the exhaust passages to the heads of the cylinders and a fourth section encloses the outer ends of the cooling passages that surround the cylinders.
The assembled pattern also includes a fifth pattern section that is connected to the second and third pattern sections and includes water passages that border the exhaust manifold passage.
The interfaces or parting lines between the first, second, third and fourth pattern sections preferably are parallel to each other and extend normal to the axes of the cylinders, while the parting line between the fifth section and the second and third sections extends parallel to a plane passing through the axes of the cylinders.
The five separate pattern sections may be joined together along the parting lines by a glue or adhesive, such as conventionally used in evaporable foam casting processes, to provide the assemble pattern.
In casting, the pattern is placed in a mold and the region between the pattern and the mold is filled with a flowable material, such as sand, which also fills the cavaties in the pattern. Molten metal such as an aluminum alloy, is introduced to the pattern via a sprue and the heat of the molten metal will vaporize the pattern. The resulting vapor is entra`pp~d within the interstices of the sand, while the molten metal will fill the voids created by vaporization of the foam pattern to provide a cast metal part which is identical in configuration to the pattern.
Through use of the pattern of the invention, the entire engine block can be integrally cast as a single unit, thereby eliminating the machining, drilling and tapping operations that have been practiced in the past when using separate covers and a cylinder block.
As a further advantage, it is not necessary to provide bosses or enlargements of the cylinder block for tapped holes, nor is it necessary to provide wide gasketing surfaces, and this provides an appreciable savings in overall weight of the engine. Elimination of gaskets and covers eliminates a significant source of leakage paths.
As the covers are cast integrally with the cylinder block, the invention elininates as many as 100 fasteners, i.e. bolts and screws, as previously used in connecting the covers to the cylinder block.
The use of the evaporable foam pattern provides greater design flexibility and enables more uniform wall thicknesses to be obtained, thereby providing more effective heat transfer and reducing the overall weight of the engine.
Other features and advantages will appear in the course of the following description of a preferred embodiment of the invention taken together with the accompanying drawing wherein;
Fig. 1 is a bottom view of the evaporable foam pattern used in casting a three-cylinder in-line two-cycle engine;.
Fig. 2 is a transverse section of the pattern;
Fig. 3 is a longitudinal section of the pattern;
Fig. 4 is a section taken along line 4-4 of Fig. 2; and Fig. 5 is a section taken along line 5-5 of Fig. 2.
The drawings illustrate an evaporable foam pattern 1 formed of a material, such as polystyrene, to be used in casting a multi-cylinder, in-line, two-cycle engine block.
While the drawings illustrate an engine block having three in-line cylinders, it is contemplated that the invention can be utilized in casting a two-cycle engine block having at least one or more cylinders.
The evaporable foam pattern is substantially identical in shape to the cast metal engine block and, therefore, the description of the components of the foam pattern will correspond to that of the cast engine block.
Pattern 1 includes a crankcase end 2 and a head end 3, and in normal usage of the engine, the crank shaft will extend vertically.
Pattern 1, as assembled, defines three cylinders 4 each having an end that opens at the crankcase end 2 of the pattern. As shown in Fig. 2, an exhaust passage 5 communicates with each cylinder 4 and is located generally mid-way of the length of the cylinder. The exhaust passages 5, in turn, are connected to an exhaust manifold passage 6, as best shown in Fig. 2 and the exhaust manifold passage 6 terminates in an exhaust outlet 7 located in a side of the pattern.
_ - 6 ~ 133365~
The two-cycle engine also includes three longitudinal transfer passages 8, 9 and lO; which are associated with each of the cylinders 4. As best illustrated in Fig. 4, each transfer passage 8 is provided with a pair of curved or radiused ends 11 and 12, and similarly each transfer passage 9 is provided with curved ends 13 and 14.
Each transfer passage lO is formed with curved or rounded ends 15 and in addition the end of the transfer passage lO facing the head of the cylinder is provided with a pair of fingers 17 which divide the passage into three sections, as shown in Fig. 4.
As illustrated in Figs. 3 and 4, the outer end of each cylinder 4 is enclosed by a dome-shaped head 18 and a hole 19 is formed in the head of each cylinder to receive a spark plug.
Water cooling passages 20 surround the cylinders 4 and a cooling passage 21 also surrounds the exhaust manifold passage 6. Cooling water is introduced to the passages 20 and 21 through a water inlet passage 22 which opens on the side of the block adjacent the exhaust outlet 7, and water is withdrawn from the cooling passages through a water outlet passage 23, which is similarly located adjacent the exhaust outlet 7 in a side of the block.
In accordance with the invention, pattern l is composed of five separate evaporable foam sections which are joined together along interfaces or parting lines. More particularly, the pattern l includes a crankcase pattern . ., 3365~
section 25, a central pattern section 26, a head pattern section 27, a head cover pattern section 28, and a water passage cover section 29.
As best shown in Fig. 3, the crankcase section 25 extends from the crank case end 2 of the pattern to a location at the lower ends of the transfer passages 8, 9 and 10, and is joined to the central section 26 along a parting line or interface A. As shown in Fig. 4, the lower ends of transfer passages 8 and 9 are curved or rounded and the parting line A is located at the tangent point between the radius of curvature and the longitudinal wall of the transfer passage.
Central section 26 is joined to head section 27 at a parting line or interface B, and the parting line B, as shown in Figs. 4 and 5, intersects the cooling water passages 20, as well as the exhaust passages 5. As shown in Fig. 5, the upper end of the exhaust passage 5 is curved or rounded and the parting line is located at the point of tangency of the radius of curvature with the longitudinal wall bordering the exhaust passage.
With this construction, the head 18 of each cylinder is located in the same foam section piece as the upper end of the exhaust passage 5 and, therefore, the critical tolerance between the head 18 and the exhaust passages will be maintained in order to provide the desired flow of combustion products across the head and into the exhaust passage.
The head cover section 28 is joined to the head section - 8 ~ 133365~
27 along the parting line C and the section 28 encloses~the cooling passages 20 that surround each of the cylinders 4.
As best shown in Fig. 3, the water passage cover section 29 is joined to the sections 26 and 27 along a parting line D
and serves to close off the water inlet and outlet passages 22 and 23, as well as enclosing the exhaust manifold water cooling passage 21. The parting line D is located normal to parting lines A, B and C and is parallel to a plane extending through the axes of the three cylinders 4.
In assembling the pattern 1, the individually cast foam sections 25-29 are attached together along the parting lines by use of a glue or adhesive normally employed in evaporable foam casting processes. The glue is the type that will be vaporized by the heat of the molten metal and the vapor from vaporization of the glue will be trapped in the surrounding sand along with the vapor generated by evaporation of the foam pattern, so that no adhesive residue will be present in the cast metal part.
Through the use of the evaporable foam pattern of the invention, the engine block can be cast as a single integral part, thereby eliminating the machining, drilling and tapping operations that had been used in the past when employing separate covers along with the cast cylinder block.
Furthermore, the invention eliminates the need for providing enlarged bosses or lands on the cylinder block that would be subsequently drilled and tapped for attachment of covers and similarly eliminates the need for wide gasketing surfaces.
8 133365~
- a -This substantially reduces the overall weight of the engine and the material cost.
In addition, the invention provides greater design flexibility and enables the cylinder walls and exhaust passage walls to have a substantially uniform thickness to obtain better heat transfer, as well as reducing the weight of metal to be utilized.
This invention rël;ates generally to evaporable foam patterns for use in casting an engine block of a two-cycle engine.
Cast metal engine blocks for multi-cylinder, in-line, two-cycle engine generally consist of a cylinder block and three separate cast covers, including two water passage covers and an exhaust passage cover, all of which are attached to the cylinder block by bolts. To provide the connection between the covers and the cylinder block, the cylinder block is formed with a series of enlarged lands or bosses, which are drilled or cast and tapped to receive bolts, and similarly mating holes are drilled or cast in the covers. In addition, the mating surfaces between the covers and the cylinder block are machined and the covers are attached to the cylinder block through gaskets and bolts. The gasketed surfaces must be provided with a substantial width to receive the gaskets and prevent leakage between the components.
In the fabrication of a conventional three-cylinder, two-cycle engine, as many as 100 fasteners, such as bolts, screws, and the like, are required to attach the covers to the cylinder block and substantial time and labor is required in machining the interfaces, tapping and drilling holes, applying gaskets and bolting the covers to the block. The intensive labor that is required is a substantial factor in the overall cost of the engine.
Furthermore, the requirement for providing bosses on the cylinder block and the increased width of the gasket surfaces adds to the overall weight of the engine.
In evaporable foam casting processes, a pattern is formed of an evaporable foam material, such as polystyrene. The foam pattern is substantially identical in configuration to the cast metal part to be produced, subject to shrinkage and/or other conditions of the casting process. The foam pattern is placed in a mold and surrounded with a finely divided medium, such as sand, 133365~
which also fills the cavatles in the pattern. When molten metal is introduced into the mold, the molten metal will heat and vaporize the pattern, with the vapor passing into the interstices of the sand, while the molten metal will fill the voids created by vaporization of the foam to provide a cast metal part having substantially the same configuration as the foam pattern. Evaporable foam casting processes have particular advantage when casting parts of unusual or complex contours.
The present invention provides an evaporable foam pattern to be used in casting a two-cycle metal engine block, the assembled pattern comprising a crankcase end and a head end, said pattern including at least one cylinder having an end open to the crankcase end of said pattern and the opposite end enclosed by a head, exhaust passage means connecting said cylinder to the exterior of the pattern, said cylinder having at least one longitudinally extending transfer passage, water cooling passage means bordering said cylinder and said exhaust passage means, said pattern composed of a plurality of separate evaporable foam sections including a first foam section extending from said crankcase end to the corresponding end of said transfer passage, a second pattern section extending from said end of said transfer passage to a location intersecting said exhaust passage, said pattern also including a third section extending from said exhaust passage to said head end including said head, a fourth pattern section disposed at the head end of the pattern and enclosing the portion of said water cooling passage means bordering said cyliner, and a fifth pattern section connected to corresponding sides of said second and third sections and enclosing the side of said water cooling passage means bordering said exhaust passage means.
The assembled foam pattern also includes a network of water cooling passages which surround the cylinders, as well as the exhaust manifold. Water is introduced into the cooling passages through an inlet passage formed in a side surface of the pattern and is discharged from the cooling passages through a discharge passage located adjacent the inlet passage.
Preferably, the evaporable foam pattern is formed of a plurality of foam sections which are joined together by glue or adhesive to provide the assembled pattern.
More particularly, the preferred pattern includes a first pattern section which extends from the crankcase end of the pattern to the lower ends of the transfer passages, and a second section extends from the lower ends of the transfer passages to a location intersecting the exhaust passages of the cylinders.
A third pattern section extends from the exhaust passages to the heads of the cylinders and a fourth section encloses the outer ends of the cooling passages that surround the cylinders.
The assembled pattern also includes a fifth pattern section that is connected to the second and third pattern sections and includes water passages that border the exhaust manifold passage.
The interfaces or parting lines between the first, second, third and fourth pattern sections preferably are parallel to each other and extend normal to the axes of the cylinders, while the parting line between the fifth section and the second and third sections extends parallel to a plane passing through the axes of the cylinders.
The five separate pattern sections may be joined together along the parting lines by a glue or adhesive, such as conventionally used in evaporable foam casting processes, to provide the assemble pattern.
In casting, the pattern is placed in a mold and the region between the pattern and the mold is filled with a flowable material, such as sand, which also fills the cavaties in the pattern. Molten metal such as an aluminum alloy, is introduced to the pattern via a sprue and the heat of the molten metal will vaporize the pattern. The resulting vapor is entra`pp~d within the interstices of the sand, while the molten metal will fill the voids created by vaporization of the foam pattern to provide a cast metal part which is identical in configuration to the pattern.
Through use of the pattern of the invention, the entire engine block can be integrally cast as a single unit, thereby eliminating the machining, drilling and tapping operations that have been practiced in the past when using separate covers and a cylinder block.
As a further advantage, it is not necessary to provide bosses or enlargements of the cylinder block for tapped holes, nor is it necessary to provide wide gasketing surfaces, and this provides an appreciable savings in overall weight of the engine. Elimination of gaskets and covers eliminates a significant source of leakage paths.
As the covers are cast integrally with the cylinder block, the invention elininates as many as 100 fasteners, i.e. bolts and screws, as previously used in connecting the covers to the cylinder block.
The use of the evaporable foam pattern provides greater design flexibility and enables more uniform wall thicknesses to be obtained, thereby providing more effective heat transfer and reducing the overall weight of the engine.
Other features and advantages will appear in the course of the following description of a preferred embodiment of the invention taken together with the accompanying drawing wherein;
Fig. 1 is a bottom view of the evaporable foam pattern used in casting a three-cylinder in-line two-cycle engine;.
Fig. 2 is a transverse section of the pattern;
Fig. 3 is a longitudinal section of the pattern;
Fig. 4 is a section taken along line 4-4 of Fig. 2; and Fig. 5 is a section taken along line 5-5 of Fig. 2.
The drawings illustrate an evaporable foam pattern 1 formed of a material, such as polystyrene, to be used in casting a multi-cylinder, in-line, two-cycle engine block.
While the drawings illustrate an engine block having three in-line cylinders, it is contemplated that the invention can be utilized in casting a two-cycle engine block having at least one or more cylinders.
The evaporable foam pattern is substantially identical in shape to the cast metal engine block and, therefore, the description of the components of the foam pattern will correspond to that of the cast engine block.
Pattern 1 includes a crankcase end 2 and a head end 3, and in normal usage of the engine, the crank shaft will extend vertically.
Pattern 1, as assembled, defines three cylinders 4 each having an end that opens at the crankcase end 2 of the pattern. As shown in Fig. 2, an exhaust passage 5 communicates with each cylinder 4 and is located generally mid-way of the length of the cylinder. The exhaust passages 5, in turn, are connected to an exhaust manifold passage 6, as best shown in Fig. 2 and the exhaust manifold passage 6 terminates in an exhaust outlet 7 located in a side of the pattern.
_ - 6 ~ 133365~
The two-cycle engine also includes three longitudinal transfer passages 8, 9 and lO; which are associated with each of the cylinders 4. As best illustrated in Fig. 4, each transfer passage 8 is provided with a pair of curved or radiused ends 11 and 12, and similarly each transfer passage 9 is provided with curved ends 13 and 14.
Each transfer passage lO is formed with curved or rounded ends 15 and in addition the end of the transfer passage lO facing the head of the cylinder is provided with a pair of fingers 17 which divide the passage into three sections, as shown in Fig. 4.
As illustrated in Figs. 3 and 4, the outer end of each cylinder 4 is enclosed by a dome-shaped head 18 and a hole 19 is formed in the head of each cylinder to receive a spark plug.
Water cooling passages 20 surround the cylinders 4 and a cooling passage 21 also surrounds the exhaust manifold passage 6. Cooling water is introduced to the passages 20 and 21 through a water inlet passage 22 which opens on the side of the block adjacent the exhaust outlet 7, and water is withdrawn from the cooling passages through a water outlet passage 23, which is similarly located adjacent the exhaust outlet 7 in a side of the block.
In accordance with the invention, pattern l is composed of five separate evaporable foam sections which are joined together along interfaces or parting lines. More particularly, the pattern l includes a crankcase pattern . ., 3365~
section 25, a central pattern section 26, a head pattern section 27, a head cover pattern section 28, and a water passage cover section 29.
As best shown in Fig. 3, the crankcase section 25 extends from the crank case end 2 of the pattern to a location at the lower ends of the transfer passages 8, 9 and 10, and is joined to the central section 26 along a parting line or interface A. As shown in Fig. 4, the lower ends of transfer passages 8 and 9 are curved or rounded and the parting line A is located at the tangent point between the radius of curvature and the longitudinal wall of the transfer passage.
Central section 26 is joined to head section 27 at a parting line or interface B, and the parting line B, as shown in Figs. 4 and 5, intersects the cooling water passages 20, as well as the exhaust passages 5. As shown in Fig. 5, the upper end of the exhaust passage 5 is curved or rounded and the parting line is located at the point of tangency of the radius of curvature with the longitudinal wall bordering the exhaust passage.
With this construction, the head 18 of each cylinder is located in the same foam section piece as the upper end of the exhaust passage 5 and, therefore, the critical tolerance between the head 18 and the exhaust passages will be maintained in order to provide the desired flow of combustion products across the head and into the exhaust passage.
The head cover section 28 is joined to the head section - 8 ~ 133365~
27 along the parting line C and the section 28 encloses~the cooling passages 20 that surround each of the cylinders 4.
As best shown in Fig. 3, the water passage cover section 29 is joined to the sections 26 and 27 along a parting line D
and serves to close off the water inlet and outlet passages 22 and 23, as well as enclosing the exhaust manifold water cooling passage 21. The parting line D is located normal to parting lines A, B and C and is parallel to a plane extending through the axes of the three cylinders 4.
In assembling the pattern 1, the individually cast foam sections 25-29 are attached together along the parting lines by use of a glue or adhesive normally employed in evaporable foam casting processes. The glue is the type that will be vaporized by the heat of the molten metal and the vapor from vaporization of the glue will be trapped in the surrounding sand along with the vapor generated by evaporation of the foam pattern, so that no adhesive residue will be present in the cast metal part.
Through the use of the evaporable foam pattern of the invention, the engine block can be cast as a single integral part, thereby eliminating the machining, drilling and tapping operations that had been used in the past when employing separate covers along with the cast cylinder block.
Furthermore, the invention eliminates the need for providing enlarged bosses or lands on the cylinder block that would be subsequently drilled and tapped for attachment of covers and similarly eliminates the need for wide gasketing surfaces.
8 133365~
- a -This substantially reduces the overall weight of the engine and the material cost.
In addition, the invention provides greater design flexibility and enables the cylinder walls and exhaust passage walls to have a substantially uniform thickness to obtain better heat transfer, as well as reducing the weight of metal to be utilized.
Claims (12)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An evaporable foam pattern to be used in casting a two-cycle metal engine block, the assembled pattern comprising a crankcase end and a head end, said pattern including at least one cylinder having an end open to the crankcase end of said pattern and the opposite end enclosed by a head, exhaust passage means connecting said cylinder to the exterior of the pattern, said cylinder having at least one longitudinally extending transfer passage, water cooling passage means bordering said cylinder and said exhaust passage means, said pattern composed of a plurality of separate evaporable foam sections including a first section extending from said crankcase end to the corresponding end of said transfer passage, a second pattern section extending from said end of said transfer passage to a location intersecting said exhaust passage, said pattern also including a third section extending from said exhaust passage to said head end and including said head, a fourth pattern section disposed at the head end of the pattern and enclosing the portion of said water cooling passage means bordering said cylinder, and a fifth pattern section connected to corresponding sides of said second and third sections and enclosing the side of said water cooling passage means bordering said exhaust passage means.
The pattern of claim 1, wherein said exhaust passage means includes an exhaust port communicating with said cylinder, the upper end of said exhaust port and the head of the cylinder being located in said third section.
3. The pattern of claim 1, wherein said first and second sections are connected together along a first interface, said second and third pattern sections are connected together along a second interface, said first and second interfaces disposed parallel to each other and disposed normal to the axis of said cylinder.
4. The pattern of claim 3, wherein said fourth pattern section is connected to said third pattern section along a third interface disposed parallel to said first and second interfaces.
5. The pattern of claim 3, wherein said fifth pattern section is connected to said second and third sections along a fourth interface disposed parallel to a plane extending through the axis of said cylinder.
6. The pattern of claim 3, wherein said transfer passage is bordered by a longitudinal wall and the end of the transfer passage facing said crankcase end is curved along a radius, said first interface is located at the point of tangency of said radius to the longitudinal wall.
7. The pattern of claim 1, wherein said exhaust passage means is bordered by a longitudinal wall and the end of the exhaust passage means facing said head is curved on a radius, said second interface is disposed at the point of tangency of said radius to said longitudinal wall.
8. The pattern of claim 1, wherein the end of said transfer passage facing said head end is disposed in said second pattern section and is spaced from said second interface.
9. The pattern of claim 1, wherein said water cooling water passage means includes a generally annular passage spaced radially outward of said cylinder and disposed in said third section, the end of said annular passage facing said head end of the pattern being open, said fourth section enclosing the open end of said annular passage.
10. An evaporable foam pattern to be used in casting a two-cycle metal engine block, the assembled pattern comprising a crankcase end and a head end, said pattern including at least one cylinder having an end open to the crankcase end of said pattern and the opposite end enclosed by a head, exhaust passage means connecting said cylinder to the exterior of the pattern, said cylinder having at least one longitudinally extending transfer passage, water cooling passage means bordering said cylinder and said exhaust passage means, said pattern composed of a plurality of separate evaporable foam sections including a first section extending from said crankcase end to the corresponding end of said transfer passage, a second pattern section extending from said end of said transfer passage to a location intersecting said exhaust passage and connected to said first section along a first interface, said pattern also including a third section extending from said exhaust passage to said head end and including the cylinder head, said third section being connected to said second section along a second interface, a fourth pattern section disposed at the head end of the pattern and enclosing the portion of said water cooling passage means bordering said cylinder, said fourth section being connected to said third section along a third interface, and a fifth pattern section connected to corresponding sides of said second and third sections and enclosing the portion of said water cooling passage means bordering said exhaust passage means, said fifth section being connected to said second and third sections along a fourth interface.
11. The pattern of claim 10, wherein said first, second and third interfaces are parallel and disposed normal to the axis of said cylinder.
12. The pattern of claim 11, wherein said fourth interface is disposed normal to said first, second and third interfaces.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US22612288A | 1988-07-29 | 1988-07-29 | |
| US226,122 | 1988-07-29 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1333654C true CA1333654C (en) | 1994-12-27 |
Family
ID=22847644
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 606967 Expired - Lifetime CA1333654C (en) | 1988-07-29 | 1989-07-28 | Evaporable foam pattern for casting an engine block of a two-cycle engine |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1333654C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113182496A (en) * | 2021-04-29 | 2021-07-30 | 广西玉柴机器股份有限公司 | Casting process design method of high-grade vermicular graphite cast iron cylinder cover |
-
1989
- 1989-07-28 CA CA 606967 patent/CA1333654C/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113182496A (en) * | 2021-04-29 | 2021-07-30 | 广西玉柴机器股份有限公司 | Casting process design method of high-grade vermicular graphite cast iron cylinder cover |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed | ||
| MKEC | Expiry (correction) |
Effective date: 20121205 |